EPA urges reuse of farm slurry as fertilisers, energy

Farm slurry could be converted into energy and high-grade fertilisers at 40 centralised anaerobic digestion plants around the…

Farm slurry could be converted into energy and high-grade fertilisers at 40 centralised anaerobic digestion plants around the State, under a proposal from the Environmental Protection Agency.

The proposal to centralise waste-management from farms and the food-processing industry could provide solutions to many of Ireland's agricultural, energy and environmental challenges, according to EPA economist Dr John Curtis.

Anaerobic digestion is the natural process of decomposition and decay by which organic matter is broken down to its simpler chemical components and converted into energy. While the plants would have significant capital and operating costs, they could make a major contribution to the economy.

In a paper circulated to Government and interested parties last week, Dr Curtis listed the benefits. They include reducing dependence on electricity from fossil fuel, and helping to reduce carbon monoxide emission to meet Kyoto Protocol targets.

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"Ground-water protection will be enhanced as after animal slurries have been processed by anaerobic digestion, they are less polluting and have an improved fertiliser value," he said.

"As a form of renewable energy, anaerobic digestion can make a significant contribution to Ireland's target under the EU Renewable Energy Directive."

The EPA hopes if consensus can be reached on the paper, implementation of some parts could make anaerobic digestion of the 132 million tonnes of organic waste in Ireland a viable business option.

Dr Curtis said the use of anaerobic digestion plants in other countries had demonstrated their benefits as a method of reducing the pollution potential of organic waste and had shown the best ways to exploit the material.

"In other European countries, the AD plants heat towns or sporting or factory complexes with steam. That could happen here too, and perhaps co-operative mart sites, which are no longer being used, should be examined."

Because it was essential for a plant's successful operation that sufficient waste was available nearby, areas where high volumes of slurries were generated would determine their location.

He said there were numerous areas with high concentrations of cattle slurry near sources of other organic material from food-processing and rendering plants.

Research had shown Cavan and Monaghan to have a particularly high concentration of EPA-licensed sites surrounded by relatively high concentrations of cattle slurry. Other counties with potential for plants were Meath, Waterford, Cork, Limerick, Tipperary, Offaly and Laois

Stressing that any such development would have to be carried out only after proper planning and licensing criteria had been adhered to, the EPA paper suggested the plants could be built by public-private partnerships.